J & K CET Medical J & K - CET Medical Solved Paper-2002

  • question_answer
    Enthalpy of\[N{{H}_{3}}\]is\[-\,46\text{ }kJ\text{ }mo{{l}^{-1}},\text{ }\Delta H\]for the reaction:\[2N{{H}_{3}}(g)\to {{N}_{2}}(g)+3{{H}_{2}}(g)\]is:

    A)  46 kJ                                    

    B)  92 kJ

    C)  \[-\,92\text{ }kJ\]          

    D)  \[-\,23\text{ }kJ\]

    Correct Answer: B

    Solution :

                     \[\frac{1}{2}{{N}_{2}}(g)+\frac{3}{2}{{H}_{2}}(g)\xrightarrow[{}]{{}}N{{H}_{3}}(g);\] \[\Delta {{H}_{f}}=-46\,kJ\,mo{{l}^{-1}}\] \[{{N}_{2}}(g)+3{{H}_{2}}(g)\xrightarrow{{}}2N{{H}_{3}}(g);\]                                 \[\Delta {{H}_{f}}=2\times -46=-92\,kJ\] \[2N{{H}_{3}}(g)\xrightarrow{{}}{{N}_{2}}(g)+3{{H}_{2}}(g);\] \[\Delta {{H}_{r}}=+92\text{ }kJ\] Hence,\[\Delta H\]of the reaction is +92 kJ.


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